Telephone-exchange system.



UNITED STATES PATENT OFFICE.

HENRY P. GLAUSEN, oF MOUN'J.1 vEnNON, AND CHARLES L. GOODB'UM, OFNEW YORK, N. Y., AssmNORs rro WESTERN ELECTRIC COMPANY, INOOBPQRATED, 0,13` NEW YORK,

NL Y., A CORPORATIUN 0F NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Muy. 6. 1919.

Application led December 17, 1918. Serial No. 287,139.

To all iff/wm t muy mim-fwn.'

Bc it known that we, HENRY l). CLAUsnN and CHAnLns L. Goounnir, citizens of the United States, residingv at Mount Vernon, in the county of llVestchester and State of New York, and at New York, in the county of New York and State of New York, respectively, have invented certain new and useful Improvements in rFelephone-EXchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to improvements in automatic telephone exchange systems, Iand has particular reference to a night-alarm service system whereby a subscriber may render his line selectable for the application of a source of signa-ling current thereto at a predetermined time.

An object of theinvention is the provision of an improved system in which an impulsestoring mechanism, under the control of a. variably operablel impulse-sending device at a. subscribers substation, is set in accordance with a portion of said subscribers number and released at a predetermined time to operate a switching mechanism which connects to the subscribers line and applies a signaling current thereto.

`Another object is to provide a step-bystep operated mechanism associated ,with a clock and adjustable to correspond with diiterent hours .of the day by the actuation of the impalso-sending device at the s11bsci'il; e1"s substation whereby said mechanism Will, after a definite lapse of time, initiate the operation ofthe impulse-storing mechanism.

The inventive idea involved is capable of receiving a variety of expressions, one of which, for the purpose of illustrating the invention, is shown in the accompanying draw ing; but it is to be expressly understood that said drawingl employed merely for lthe pur'- pose of facilitating the description of the invention as a. Whole and not to define the limits thereof, reference being had to the appended claims for this purpose..

Thedra-wing is a diagrammatic. illustration of the circuits and mechanism employed for enabling a. subscriber toha-ve his bell rung at a. predetermined time.

4 In the preferred embodiment shown, there is provided at the. central office of an automatic exchange a time-controlled signaling apparatus sslectbleby the subscriber at sabstation A through line finder and lselector switches B and C of any desired construction, and set in accordance with impulses transmitted from said substation. Said apparatus consists of an impulse-storing mechanism D, the two units d and ci ofy which are designed to receive impulses corresponding to the tens and units digits respectively of the subscribers number. The apparatus further comprises a step-by-step mechanism E also under the control of the subscriber at substation A and adjustable to correspond to diii'erent hours of the day. Associated with this mechanism is a dial F including hour land quarter-hour contactA segments f and f respectively, and movable over these segments is a brush or wiper f2 controlled by a clock (not shown). At a predetermined time after the setting of mechanism E, wiper f2 movable with the hour hand of theiclock, will enga-ge an hour .segment f and one of the quarter-hour segments f associ-ated there-- Ywith and thereby establish certain circuit changes to successively release. the units d and d of the impulse-storing mechanism. whereby the impulses delivered therefrom will operate a direc-tively controlled 'switch' G sinlilar to a connector and arranged so that' its brushes will coperate with the multiple terminals of the regular vconnector bank. Under the control of the impulses, switch G is connected to the line of substation A and signaling current is then applied, provided the line is not otherwise busy. Should the linoV be busy, this. signaling current WillV be applied upon the' hanging up of the receiver at substation. A providedwiper f2 has not "moved off of the particular quarter-hour segment f. K

Specifically, a subscriber at substation Wishing to have his bell rungF at acertain time, irst removes his receiver to automatically operate the line finder B, and u on seizure of the subscribers line, said ine finder will extend the line Vto selector switch C. The subscriber now manipulates his impulse-sending device to set the selector C on a level of trunks leading to a time-controlled apparatus at the central. olice exchange, and the brushes of the selector then automatically seize an idle trunk leading to one of these apparatus in the usual manner. Line re ay 100 of the selecting mechanisms I)` and, is new ensred- .over e circuit y At the termination Q extendin from grounded batter left winding of re tty- 100,- lower side of t e tele hone Ime,- substatlon apparatus A upper s de o-f the telephone line and right winding of relay 100 to glround. Slow-to-,release relay 101, due to t Ve energization "of relay 100, 1s also operated by the circuit extending fromgroundcd batter winding of relay 101, front contact and' armature of .relay 100 to ground. The operation of relay 101 places round at the left armature thereof and lestallllshes a bus test to prevent seizure of the time-control ed .apparatus by an)l other subscriber. Relay 102 is now energized over a circuit extending from grounded battery, winding of said relay, olf-normal contact 103, front contact and lef't armature 4of relay 101 to ground, and said relay is locked up by a circuit extending from grounded battery, winding of relay 10 front contact and right armature thereof, front contact and left armature of relai 101 to round` Slow-to-release relay 104- 1s ener 1 zed by the circuit extending from oun d battery winding of relay 10-1` ront Contact and left armature of relay 102 to ground. Relay 104 in attracting its armature removes the ground therefrom. The ...subscriber may now manipulate his sending device to transmit impulses corres onding to the `tens digit of his number. pon the first retraction of the armature of .linerelay 1.00, a circuit is closed for slowto-releasc rela 105 extending lfrom grounded battery, win ing of said relay, front contact and right armature of slow-to-release relay 10,l gb,alcll contact and right armature o f reiay 10o aground. muys 101 and 105 remainenergized dur-ing the sending of impulses. .Escape magnet 106is also ener ized y the circult extending from groundet batter". winding of magnet 106, front contact an armatureof relay 105 to ground, said clrcuit being also maintained While impulses are sent.

Side-switch wiper 107, being invits first psition will cause the impulses of the tens lgirtv the number to be transmitted to the primary stepping magnet 108 of .the unit d .oyer a circuit extending from grounded battery, Winding of magnet 108, W1per-107, front contact and right armature of relay 101 baclrcontact .and armature of relay` 100 to ground. Upon each energizationof the magnetlOS, its armature operates the. ratchet lwheel109 and assoc1ated ,c ontact-arm 110, and insedoin a coil spring111havi n o ne end secure to sai contact arm and its other end to ylange ratchet Wheel 112', is laced under tension. i): the vtransmission of the set of impulses to the. unit ,ai of the Stor- 'ing mechanism, relay 105 .releases and breaks circuit fonthe escape magnet 106 thus causing the side-switch@ wiper' 107' to' move to position 2. Movement of the sideswitch wiper operates off-normal contact 103, which remains in its operated position until the sideI switch is again returned to normal.

Unit d of the storin mechanism.- is nc-w selected for reccivin t e unit impulses of the subscribers num crand in res use to the first impulse slow-to-release re ay 105 and escape magnet 106 are again energized and a circuit closed -for stepping magnet 113 of unit al extending from rounded battery, winding of said magnet, si e-switch wiper 107, in osition 2, front contact and armature of re ay 101, back contact and armature of line relay 100 to ground. Magnet 113 continues to operate 1n response to the impulses transmitted, and in attracting its armature steps small ratchet Wheel 109 around to tension the spring' 111. inthe same manner as described in connection with unit d, the large ratchet Wheel 11?/ remaining stationary. Arm 110 of unit d o crates olf-normal contacts 114 which are c osed upon the first step of ratchet wheel 100 i101l a purpose which will later appear. When this set of impulses ceases, relay 105 and escape magnet 106 are again denergized and side-switch Wiper 107 is moved to position 3.

In accordanre with any suitable code, the subscriber may now' dial his impulse-sending device to transmit the necessary number of impulses to adjust the step-by-st'ep mechanism E to correspond with 'the particular time he Wishes his bell. to be rung. Two sets of'impulses are required for :this purpose, and in response to the first set, stepping magnet 115 is energized over a circuit extending from grounded battery, winding of said magnet, Wiper-107 in position 3, front Contact and right armature of relay 101, back contact and armature of line relay 100 to ground. In attracting its arma-ture, magnet 115 steps ratchet 116 and wiper 117 onto the desired terminal in the bank corresponding to .the hour at which the subsoribers hell is to be rung. At the termination of this set of impulses, escape magnet '106 is against released,y as previously described, a nd wiper 107 is moved into position 4. The -last set of impulses determines the quarter-hour at which the bell is to be rung, and if this time is on the hour, only one impulse need be transmitted in order to step the ratchet l118 and Wiper 119 onto the first terminal in the associated bank. To' accomplish this stepping operation, magnet 120 is energized over a circuit from grounded battery, Winding of said magnet and wiper 107 in its fourth osition to ground4 at the right armature o Iline 'relay 100, as previously set forth. Escape magnet 106 was a ain energized ,daurinV the transmission o the last' set of' impnses, and at tlie termination thereof seid' 'magnet isfegein released und 'Wiper '1'07 'moved Into position After opertil'g lust' time, tlle sullseriberj et substation-PA liirg's up his receiver and causes the release of line relay 100, which initurn releases lfirst slowt`oreleasey relay 101 and "rernoves ground" the front eentstet end left :trmture lthereof. Remorelef grgu-nd breaks 'the loekin eiieuit'orrely 102,' l"and in: releasing its yle t armturetlsof'brezkslthe Ciiiietixit .forIsloWfto-releitse relzty 104, mid the arr'n'ature of tlie 'letter iela'j'f A"Willi `engetgeV bekfcolitalet'and ljlaee grountlupon the test Wire; Whioleauses Ltlie seme to `test "busy tov a selector 'siiteh 'C operated llyany other subscriber. Tt Will 'be apparent "thaty since remy lOl-t lis fslow to release,l f; "Certain jintervel" of tinvi'e Willgelapsefbetweer the removt'tlE of groundetthe left armature of rrelay 101an'd theple'ng ofgounl onfthe lit armature ofreley 104i, and no `ground fing hou the test Wire duringlithis lntervelyt'lie seleetor sdi'teli (l endl-line 'finder By *will 'be released in ze'coxjda-nce with ythe welll-known rstet'iee. The storingvmelianism D; and stepiby-step melienisrn E' tre jiioW set ,endfre'lneil'n in "this positiony 'until Ithe'predeterni-'inel TAtime indicated .bj1 the setting of the 'm'e'eheni'sm E arrives.

nergizltionf said relay, endrwtlle n Lolosefs e cirenitff line @meer G weeding. from i {ft wiijdig fjfeley, 201,

lts'arm Te",L lelost'ss 'e circuit for' first "s oWto--releese l relztyZOQ eXd tending yfrom grounded bettey,' f6ntcon-` his se1iding"leviee the @matieres pf' freely lei "are animee.

yf; @meer 'we we Y* conduct@ i255", .enter lef j -`land fonte'ontaet of lrelejy .121 eri' lling f' relayeor mend." Res in retreating its `ermee-e Ireleases ratchet 7o 112 lvshidh, under 'the influence jdflthe springI l`1l Whili-*Was' 'eviouely teneioneel, moves ero'uml 1in ai Cloe Wise rli'rection'nntil Contact 127 @drilled-therebyengageserin110; iper fmofvalil-e with lfeteliet 1l-1Q lentlll'en- 75 gges'thie serie'sfoifl contacts tied to 4e'oi'oluctor- 195 f and eorisequently interrupts tlie'eii'euit of linerelsty 201 in accordance with "the nlnberef f impullses `etretl" iny theeunit d, whereby "the `-lorusliesof the connector G Sb? befstepped in response to' 4seid impulses. Upon engagement df eont'aetflf''ivith 1`1'0`, tlie transmission of "tens iiripilsesw'ill eeaseitnd a. eil-Cuit Vwill be "elosed ite relee'se the impulses stored' in Vunit d', which eirclrit 85 extends .'fro'ni grounded battery, Winding di releasey Ine-gilet' 126', oil-normal contacts 114, which 4were yclosel upon the first' step of ratchet f 109', eb'rite'et 127 end'erjn 1'10'to ground, Magnet 126 in attracting its 90 eiineture,`releases large ratchet l112 wliih, under fthel vControf'l of spring' 111", nieves Wiper '3124' *offer-"the" terminalI yconteets oil? conductor yto again interrupt ther-circuit for relay '201, whereby the impulses from 96 u'nit LZ lare delivered to 'again step the brushes ofeonnee'tor .Gr onto terminetls of the slibslcri-bers"-lie. i 4 z f to the irstset ofjlnpllses from' unit" d; second slmvv-to'release` relty Qhils initiel'ljf".renergiZed over itfei're't extentlngffromfgrounded buttery; windin ofrele; '203, froiiit Contact endermeture o relay-202, back jcontact and' armature lof rela?? 20H to 'gromrd The operttion of rely 21 3 also causes escape magnet 204fto energivze over e" eir'euit 'extending from :grounded battery, Winding "of eseepe lmegnet 2,2045 front eonta'et 'and ermetre of relay 4ZOB'jt` ground. @Simultaneously primary stepping' magie. :2.05 .is brewed; hier ,erwerben teni .111g 'frere' :gfeurlted batteryindn' I weerJzoigsieewier wiperiseo .es pesijtiong' inem .conflict y"mld armature: er reley 202; ylfeclr"dontect "endl lerineitlure bf re?" 111% lay 2,01`to ground, "and'rin res'lpnseito estelle im uleeyfef "the first. eet; 'shipping magnet e termination f ...le e ,fy 20H6. rgles. edire- Ieases escjjpemmegnet f2 I "which Moves: wipers ofthe 4side syviteltinto position 2,'er'1d` in` 'response'zto units' impulsesg @from unit: W;

, energized by e erepaeemaiw fgro temi; eineihgvee' eww; wi er eeefneiee e first ',setj 132e its, second position, front contact .and-.armar turegpf relay 202, back contact and.armary tureof relay` 2.0.1 to .g1-Gund... The brushes fV the connector Gr are stepped by magnet 207 onto the terminals xto; which. thembscrbers line is connected ,and ifthis` line' sli'ou'ldsbe busy, thisI condition -gbein rdenoted by ground atv the. test .termina a circuit. for test relayy 208 is closed extending from grounded battery, Winding of lrelay y208,f side-switch wiper 209 .inits :second position and `test brush 210 l.to groundl at the busy terminal. Relay 203. closes thecircuitor escape magnet 2051 extending yfrom grounded battery, Winding 0f. magnet ,204,.fr01it cantact and armature of relay 20S to ground, and this circuit ishestabl'ished before slowtu-.Itelease relay, 203 denergzes, thereby preventing lescape magnet 204,v from releas,n ing to step .the` lWipers of the side. switch to position. ,'lhe sideesvvitch,l Wipers. will. remain in vposition 2 as-long as the subscribers line; remains busy, provided Wiper f? does not .disengage 'contact f before.the subscriberwat substation Anhangs up his receiver,- Whlclig Would othervyise'breal'. the circuit for A'relay 121 land -canse the. `release of mechanism E andswitch G in ya mannerv which will presently be described. Should the subscribers line be idle, re` lay208ynding no ground at the test terminal of the line, `will not. energize, and atl the termination of the last setpfimpulses IQlay ..203 will release. :and .Cause .eSQPe magnet .1204. ,to stepthe lfside-switch wipersr intov position 3, The .ringing current will, immediately be applied vto r.the subscribers li'iiepovera circuit extending'ffromfa grounde d.:'sourcel of ringing. current, ,Winding oi marginal .rlay.f211,side-Suit@ Wiper 21,2., MUS. 213. apparatus at subst-stiva A.. brush. .2.145. and Side-.Snitch Wiper 215 .to ground. This ringing-current may be lap] plied in acharacteristic manner and' will continue until the subscriberr at substationl A. removes.' his' rver...R1ay .211..beins4 marginal; will-mt at'tatits. armaturedring 'the -t-,methafg ringing enrrent.;.is"gbejng, applies.- and ai .Sherfim 'twforrelay'. 200.! will :he maintained. Whisk.. .ill previ-ent this' relay .fill-.liecom ...energized upon' the firststp O lftlie. brus 'eS'.,0.-the switchfrom.I theilias'mial. PSti-n .Tleslshort Qreiifl @2itends from? grouhdebattery. :armature and. back. contact, .of'rel'ayc 211,1, armature baskslilltiltsof.` @X292 resistaiieef2l-6/alid. Qf`uori1iar10utiot-217 to. .ground-f The 1re-.f moral. et..the.re '=aref lee/baume of. @ratas-'relay .211. .tl/11d. in ...erung .its arma ture, the short circuit for relay..200. is brekeeandrthe .lat-ter relay. will .immediately eerszanver. a. aimait.. extending. .from gravedad battery.' winding. fof ...relay 209. rev Sist-anbel .an ,..olif-uormal-.ieontact 217 toi errand-JF broken at the back contact and right armature ofrelay 200, rwhich causes the right armature 1of, relay5 121 to release and disengage theassociated pavvl from ratchet 116 in accordance with the constructionfin the above referred to patent, and as consequence of this movementjofl the armature, pawl 122 Will be disenga .ed from the ratchet 118.

through the lme ium of rod 123. Right' armature olf'relay 121 and i aWl 122 will remain out of .engagement with their ratchets until re1ay.115"i s again energized to ste wiper. 117-r inalnewsetting of mechanism Wipers 117 and 119 and their associated ratchets Willthenzbe" returned to their normal positions `under thel influence of a spring ,motor .or other similar mechanism (not shown) I'c Ihrough.any mechanical connection IWell known inthe art,sideswitch mechanismwincluding Wiper 1 07 is also returned to normal uponfthe release of mechanism E. Release of relay 121 causes-the outerleft armature thereof to break the circuit for line relay 2,01, which, upon deenergizatiomnligeleases relay 202 andv closes a circuit for release magnet 218 extending from grounded battery, Windin of said magnet, olf-fnormal vcontact 219, ack contact land '..armature of relay 202, back contact and armature of relay 201 `to ground, iand. .through `the operation of magnetg2l8,;tlie several side-'switch wipers and oit-,normal @ontacts .are returned. to

normal position y .Movement of Wipers .212; and: 215 ,fromposition 3 releases relayv 211,. andlupon the return ofoI-normal contact 217 gtonormal position, relay 20,0 be-l comes denergized, v,and the switchis again in its vnormal. position `and the subscriber may hangnp h1 s ,receiver. v

ylNhat is claimedis: 1, v11u an, .autsmatie telephone emballe@ s st emLa telephone line, an impulse-sending evice, an y impulse-storing mechanism, means. controlled by saidsending device to determine the period of ,time necessary: to expire before said' v.storing mechanism is rreleased fand. means. actuated. by the ,release ofllsaid ,.szoriiig. `mechanism for connecting.

a ysignaling current to saidtelephoue line. n

In. an :,automatiofftelephone exchange system, atelephoneline, a variably operable impulse-sending device, animpulselstoring mechanism, electromagnetic means con-y trolled said sending device for,transmit-v ting impulses to: said storing mechanism, aI

stepby-step operated mechanism also controlled by said4 sending device to determine, the y .periodi time necessary. to .expire be;v fore said Ystforin mechanism is released, and' means actuated y the release of said storingg dev-ice'. :fory ,connecting a I'signaling current to said telephone-line.;

3. In. an .automatic telephone exchange he cincuiaivn..relay.121,is. theny system, a .telephone f1ne an, impulseesending.

ino

device, an impulse-storing mechanism, means controlled by said sending device' to determine the period of time necessary to expire before said storing mcclianisi'1xis released, and a switching mechanism operated in response toimpulses from said storing mechanism after the same is released for connecting a signa-ling current to2-said telephone line.

4. In an automatic telephene exchange system, a telephone-line, a varia'bly operated impulse-sending device, an impulse storing mechanism, electromagnetic means controlled by said sending device for transmitting impulses to said storing mechanism, a step-b -step operated i'nechanism also controlle by said sending device to determine the period of time necessary to'expir'e before said sturing mechanism is released` and switching mechanism operated in response to impulses trom said Stor-ing: mechanism after the same is released for 'connecting a signaling current to said telephone line.

5. In an automatic telephone exchange system, a telephone line, an impulse sending device, an impulse-storing mechanism` electromagnetic means for releasingfsaid storimf;- mechanism, means operableat a predetermined-time after the actuation -of said sending device for rendering said' electromagnetic means effective, and means actuated ancew-ith certain digits of the subscriber-s num ber: from-said .sending-.device'to said| impulse-storing i mechanism, :electromagnetic means for releasing' said storingmechanism, a' step-by-step `operated mechanism also-.con- .trclled' by said-sending de'viceand operable at theI terminationof a.- predetermined .pcriod ottime after# the tuansmission--offimpulses tofsaid storing mechanism fun-rendering said electromagnetic means effective, and -means operated upon they yrelease 4of said storing mechanism i for connecting a; signaling current to 'said telephone line.

9. In an automatic. telephone exchange system, a telephone line, an impulse-storing mechanism,` adjustable means fior controlling thereleasectf impulsesfrcm said storing mechanism, an impulsasendingtdevice fori transmitting., impulses. to i said storing mechanism and adjustingxsaid; adjustable means fin accordance-with a. definite time of the days, fmeansantuated at said definite'timc for causing said adjustable means :to initiate ,the operation .of said ,storing mechanism, and` means responsive to the impulses from said storing mechanism for connecting a signaling current to said telephone line.

'10.' In 'an automatic telephone exchange system, autelephone line, an impulse-storing mechanism, a step-by-step operated mechanism lforicontro-ll-in'g the releaseI of impulses by the release of said storing device frcon-'fcfi" said storing mechanism, an impulsenecting a signaling current to said telephone line.

6. In an automatic telephone exchange system, a telephone line, an impulse-storing mechanism, an impulse-sending device for operating said mechanism, means responsive' to said impulse-sending device to determine the time at which said' storing mechanism will be released, means for rendering the last named means effective, and a switching mechanism set by impulses from said storing mechanism after the same has released to ponnect a signaling current to said telephone 7. In an automatic telephone exchange system, a telephone line, impulse-sending device under the control of the subscriber, an impulse-storing mechanism, switching means for transmittin impulses in accordance with certain diglts of the subscribers number from said sending d'evice to said impulsestoring mechanism, means also controlled by said sending device to determine the period of time necessary to expire before said storing mechanism is released, and means actuated by the release of said storing mechanism for connecting a signaling current to said telephone line.

8. In an automatic telephone exchange system, a telephone line, an impulse-sending device under the control of the subscriber, an impulse-storing mechanism, switching means for transmitting impulses in accordsending device for transmittin impulses to said storing mechanism and a justing said step-by-step operated mechanism in accordance with a denite time of the day, means actuated at said definite time for causing the initiation of the operation of said storing mechanism, and means res onsive to impulses from said storing mec anism for conpecting a. signaling current to said telephone 11. In an automatic telephone exchange system, a substation apparatus, a variably operable impulse-sending device thereat, an impulse-storing mechanism for receiving impulses from said sending device, other mechanism set in accordance with impulses from said sending device to determine the time at which said storing mechanism shall be released, and means controlled by the impulses frorn said storing mechanism for connecting a signaling current to said substation a paratus.

y12. n an automatic telephone exchange system, a substation apparatus, a variably operable impulse-sending device thereat, an im ulse-storlng mechanism for receiving impu ses from said sending device, other mechanism set in accordance with impulses from said sending device to determine the time at which said storing mechanism shall be released, means actuated by said other mechanism at the expiration of a predetermined leugth of time for releasing said storing mechanism, and means controlled by impulses from said storing mechanism for connecting a signaling current to said substation apparatus.

13. In an automatic telephone exchange system, a substation apparatus,- a variably operable impulse-sending device thereat, an impulse-storing mechanism for receiving impulses from said sending device, -other mechanism set in accordance with impulses from said sending device to determine the time at which said storing mechanism shall be released, electromagnetic means controlled by said other .mechanism and operated a definite eriod of time after the'setting of said ot er mechanism for releasing said storing mechanism, and means fcontrolled by impulses from said storing mechanism for connecting 'a ysignaling current/:to said substation apparatus.

14. In an automatic telephone exchange system, asubstation apparatus, a variabiyoperable impulse-sendingV device thereat, an impulse-storing mechanism for receiving impulsesfrom' saidsending device, a stepby-step operated mechanism set in accordance with: impulses. `from said sending device to determine the time-at which said storing mechanism sha1-l be released, circuits for Copies of this patent may he obtained for controlling the release of said storing mechanism, electromagnetic means operated by said step-by-step mechanism for successively closing the circuits of said storing mechanism at the expiration of a predetermined length of time, and means responsive to impulses from said storing mechanism for connecting a signaling current to said substation apparatus.

15. In anautomatic telephone exchange system, a substation apparatus, an impulsesending device thereat, an impulse-storing mechanism, means for releasing said storing mechanism, a step-by-step mechanism set by said sending device to actuate the last named means at the termination of a definite period of time after the setting of said stepby-step mechanism, a lswitch responsive to the impulses from said `storing mechanism for connecting a signaling current to said substation apparatus, and means for returning said step-by-step mechanism to normal position upon the removal of the receiver at said substation apparatus.`

In Witness whereof, We hereunto subscribe our names this 12th'day of December, A. D., 1918.

HENRY P. CLAUSEN. CHARLES L. GOODRUM` tive cents each, by addressing the "Commissioner of Patents.

Washington-B. 0. 

